Retinal vein occlusions happen when a blockage occurs either in the main vein of the retina or a smaller branch point in the retinal venous circulation. Since the main function of retinal veins is to carry blood away from the eye and back to the heart (retinal arteries bring blood into the eye from the heart), blood backs up in the retinal circulation, causing congestion forcing blood out of the vessels and into the retina. This causes bleeding and swelling in the retina, resulting in blurry vision and retinal damage. Vein occlusions tend to be associated with underlying high blood pressure, diabetes and glaucoma. They can also occur, however, in the absence of any underlying systemic disease. Vein occlusions can cause blurred vision and in some cases the perception of floating spots.

Central Retinal Vein Occlusion

Branch Retinal Vein Occlusion

What treatment is available for retina vein occlusions?

Retinal laser treatment may be helpful in stabilizing retinal swelling and preventing more bleeding, but in many cases it cannot restore vision. Retinal swelling may also be treated with special medications, which are injected painlessly into the vitreous cavity, but this therapy is considered experimental and needs to be proven in controlled research trials. The role of retinal surgery is less clear, and further research is needed to prove its long-term efficacy.